1. Technical Field
This invention relates generally to current limiting devices and, more particularly, to current limiters for preventing excessive current supply and providing self-recovery characteristics.
2. Discussion
Due to the relatively high current drive capabilities of a chip, an excessive amount of current may be drawn by the chip's active circuitry upon power up or an illegal operation of the chip. As a consequence, this excessive amount of current may result in damage to the chip. As a means of protection, it is therefore generally desirable to employ a current limiter for limiting the amount of current supplied to the active circuitry of an integrated circuit or chip.
Protective current limiting devices have been developed for preventing excessive current supply to the active circuitry of a chip. Conventional current limiting techniques have included the use of an external circuit breaker made up of discrete components. Other techniques have included the use of a current limiting transistor with a selectively coupled resistor. These techniques generally monitor the current supplied to the chip and prevent excessive current flow thereto by either disconnecting the power supply or limiting the power to a maximum preset level.
Conventional current limiting techniques such as those which employ an external circuit breaker, generally limit the amount of current supplied to a chip by shutting off the chip's power supply upon detecting excessive current. However, such techniques, by themselves, leave the chip inoperative. In addition, such techniques generally do not correct the problem that caused the excessive current demand. In order to allow for proper operation of the chip, it is generally required that the problem which caused the excessive current be corrected and the circuit be reset.
Conventional techniques have typically required external components and the need for an operator in order to re-energize the chip. In addition, an operator and external components are further required to correct the problem causing the excessive amount of current. For applications such as those involving unmanned vehicles and the like, it is desirable to have a current limiter with self-recovery characteristics for automatically putting a chip back into operation and which does not require an operator or excessive external components.
It is therefore desirable to obtain a current limiter which prevents excessive current supply and provides for self-recovery characteristics. It is further desirable to obtain such a current limiter which does not require excessive external components. In particular, it is desirable to provide for such a current limiter which may operate to prevent excessive current supply to the active circuitry of a chip and to allow self-recovery thereof.